Exchange and Transport Flashcards
1
Q
what is the need for specialised exchange surfaces
A
- take in products for metabolic reactions
- excrete waste products of metabolic reactions
2
Q
why is diffusion slow in multicellular organisms
A
- cells are deep within the body
- large animals have a low surface area: volume ratio
- higher metabolic rate so use products faster
3
Q
what are specialised features of multicellular organisms
A
- large surface area
- good blood supply
- good ventilation
4
Q
how do root hair cells have a large surface area
A
- each branch has millions of microscopic hairs
- gives large surface area to increase the rate of water and mineral absorption from the soil
5
Q
how do alveoli have a large surface area
A
- each alveolus is made from a thin alveolar epithelium
- oxygen diffuses out into the blood
- carbon dioxide diffuses in the opposite direction
- thin alveolar epithelium decreases the distance that oxygen and carbon dioxide diffusion take place
6
Q
what is cartilage
A
- has tracheal rings
- support trachea and bronchi to prevent it from collapsing
7
Q
what is ciliated epithelium
A
- along the trachea down to the bronchi
- sweep mucus, dust, bacteria upwards and away from the lungs
- prevents lung infections
8
Q
what are goblet cells
A
- scattered throughout the cilia
- secrete mucus that traps dust, microorganisms and bacteria from reaching the lungs
- swallowed and destroyed by stomach acid
9
Q
what is squamous epithelium
A
- forms alveolar wall and is very thin
- permeable for easy diffusion of gases
10
Q
what is smooth muscle
A
- walls of bronchi and bronchioles
- regulate the flow of air into the lungs by dilating when more air is needed and constricting when less air is needed
11
Q
What are elastic fibres
A
- enable the lungs to stretch and recoil
12
Q
what is the nasal cavity
A
- large surface area with a good blood supply
- hairy lining to secrete mucus
- moist surfaces reducing evaporation
13
Q
what is the trachea
A
- carries clean warm air from the nose into the chest
- supported by cartilage to help move food
- lined with ciliated epithelium and goblet cells
14
Q
what is the bronchus
A
- trachea divides to form left bronchus going to the left lung
- forms right bronchus going to the right lung
- supported by cartilage
15
Q
what are bronchioles
A
- bronchi divide to form small bronchioles
- small bronchioles have no cartilage
- smooth muscle contracts bronchioles constrict
- smooth muscle relaxed bronchioles dilate
16
Q
what are alveoli
A
- small air sacs
- flattened epithelial cells, collagen, elastic fibres
- elastic recoil - alveoli stretches when air is drawn in and squeeze air out when resting
17
Q
what are the adaptations of alveoli
A
- large surface area
- thin layers for a short diffusion distance
- good blood supply - maintain carbon dioxide and oxygen concentration
- good ventilation
18
Q
what is the process of inspiration
A
- external intercoastal and diaphragm muscles contract
- ribcage moves upwards and downwards
- diaphragm flattens increasing volume in the thorax
- lung pressure decreases
- air flows into the lungs
- active process so requires energy
19
Q
what is the process of expiration
A
- external intercoastal and diaphragm muscles relax
- ribcage moves downwards and inwards
- diaphragm curved again
- thorax volume decreases, air pressure increases
- air is forced out of the lungs
- passive process - no energy needed- but can be forced
20
Q
what is a spirometer
A
- person breathes in and out and the lid of the chamber moves up and down
- movement recorded by a pen attached to the lid of the chamber creating a trace
- soda lime in the tube absorbs carbon dioxide
21
Q
what is tidal volume -
A
- volume of air that moves into and out of the lungs with each breath
22
Q
what is vital capacity
A
- volume of air that can be breathed in or out
23
Q
what is the inspiratory reserve volume
A
- maximum volume of air you can breathe in
24
Q
what is the expiratory reserve volume
A
- extra amount of air you can force out of your lungs
25
Q
what is residual volume
A
- extra amount of air you can force out of your lungs
26
Q
what is total lung capacity -
A
- sum of vital capacity and the residual volume
27
Q
what is breathing rate
A
- number of breaths taken per minute
28
Q
what is ventilation rate
A
- total volume of air inhaled in one minute
29
Q
how do you calculate ventilation rate
A
tidal volume x breathing rate
30
Q
how do fish exchange gases
A
- water containing oxygen enters through the mouth and passes out through the gills
- gills made of primary lamellae giving a big surface area
- gill filaments covered in secondary lamellae giving a large surface area
- gill plates have lots of blood capillaries and a thin surface layer of cells to speed up diffusion
- blood flows through the gill plates in one direction and water in the other - counter current system
31
Q
how do fish carry out ventilation
A
- opens mouth and buccal cavity lowered to the floor
- volume of buccal cavity increases decreasing pressure
- water is sucked into the cavity
- volume decreases and pressure increases
- water is forced out of the cavity across the gill filaments
- each gill is covered by a bony flap (operculum)
- when pressure is increased the operculum on both sides is forced open allowing water to leave the gills
32
Q
how do insects exchange gases
A
- air moves into the trachea through spiracles
- oxygen travels down the concentration gradient towards the cells
- carbon dioxide moves towards spiracles to be released in the atmosphere
- trachea branches into tracheoles that have thin permeable walls - fluid where oxygen can dissolve
- oxygen diffuses from the fluid to body cells
- carbon dioxide diffuses in the opposite direction
